I think as long as there are as many buyers as sellers Ebay will always be a success. I use ebay alot. I started out as a buyer but have become more of a seller, it was fun to search for neat stuff. I admit Ebay has alot of new cheap junk listed for sale every day but if you look deeper there are real items of value all over the site. By real I mean stuff that you might only be able to find by spending days or weeks snooping around in specialty shops. Example.. I was looking for an aeronautical item to decorate a cabin wall. It had to be something different that you couldn't get at the mall. Within 3 minutes I found just what I wanted. It was a set of tail rotor blades from a Huey helicopter. I had them in my hand about a week later. I also bought my Matrox Quad card and lots of other good finds on Ebay. Its just plain fun to search for stuff and its even more fun to sell things on Ebay. I have watched this fun spread to both young kids and old folks who have learned to use a computer just to use Ebay. One other thing that they have going for them is cost control. If business slows down for a while they just shut down a few dozen servers, no warehouses to close or sell. I think as long as it is fun, easy and safe to use Ebay they will always find and keep customers. The stock value is a whole different matter. I don't think I would want Ebay stock to be a "large" part of a long term portfolio but than again my long term portfolio is holding stocks for 1 week or less. 

